[gtk+] csd: Implement middle-click action for titlebar

[Matthias Clasen <matthiasc src gnome org>]

commit 35a4bba9027b2c17ed98dfc78445224379e682ec
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Aug 13 18:24:37 2013 -0400

    csd: Implement middle-click action for titlebar
    
    The default middle-click action on the titlebar should be to lower
    the window. Implement that.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705809

 gtk/gtkwindow.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index a74ab7e..1210acf 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -7179,6 +7179,13 @@ gtk_window_button_press_event (GtkWidget      *widget,
                   return TRUE;
                 }
             }
+          else if (event->button == GDK_BUTTON_MIDDLE)
+            {
+              if (region == GTK_WINDOW_REGION_TITLE)
+                {
+                  gdk_window_lower (gtk_widget_get_window (GTK_WIDGET (window)));
+                }
+            }
         }
       else if (event->type == GDK_2BUTTON_PRESS)
         {